Domed structure for demolition and method of demolition

ABSTRACT

A method of modifying a domed structure for demolition comprises forming a hinge or pivoting arrangement in a wall of the domed structure. The hinge arrangement allowing the domed structure to rotate about a reaction line for controlled demolition of the structure. The domed structure can be modified with additional openings in the dome and wall for explosive charges to facilitate the demolition.

[0001] This application claims priority based on provisional patentapplication No. 60/355,754 filed on Feb. 12, 2002.

FIELD OF THE INVENTION

[0002] The present invention is directed to a domed structure and itsmethod of demolition, and particularly to demolition of nuclear reactordomed structures using a hinge arrangement to direct the domed structurein a desired direction during demolition.

BACKGROUND ART

[0003] In the prior art, various techniques are employed to demolishbuildings. One technique involves the use of a hinge structure. In thistechnique, a “hinge” is built within the structure to be demolished. Thehinge is formed from concrete and/or rebar, and is typically installedwithin the structure to be demolished. The hinge is positioned andconfigured with the appropriate explosives so that once the explosivesare detonated, the hinge defines a pivot line for the structure to fall.The hinge aids in directing the structure along a predetermined fallline, so that surrounding buildings are not damaged. Identification ofthe fall line also allows the demolition team to prepare the ground forimpact.

[0004] While it is known to use hinges to take down buildings that havea large height to diameter ratio, e.g., a chimney, domed structures aremore problematic, particularly nuclear reactor domed structures. Oftentimes, the walls of the containers are four feet thick, the height todiameter ratio is far less than is found in chimneys, grain elevatorsand the like. Consequently, there is a need for improved techniques fordemolishing nuclear reactor domed structures as well as other domedstructures of substantial mass.

SUMMARY OF THE INVENTION

[0005] It is a first object of the present invention to provide a methodof demolishing domed structures.

[0006] Another object of the invention is a method of demolishing domedstructures using sides of the structure to assist in the demolition.

[0007] A still further object of the invention is a method ofdemolishing domed structures that utilize a pivoting mechanism or hinge.

[0008] One other object is modified domed structure that employs thehinge or pivoting mechanism as a part thereof.

[0009] Other objects and advantages of the present invention will becomeapparent as a description thereof proceeds.

[0010] In satisfaction of the foregoing objects and advantages, theinvention includes both a method of demolition and a domed structureconfigured for such demolition.

[0011] In the method aspect of the invention, the method is animprovement in demolishing a structure using explosives, the improvementcomprising forming a pivoting mechanism in a wall portion of thestructure to direct the structure along a predetermined fall line. Moreparticularly, the method entails the steps of segmenting a dome of thedomed structure and forming a pivoting mechanism in side walls of thedomed structure along a reaction line. Openings are formed in opposingwall portions, one wall portion facing a direction of intended fall.Support portions of the one wall portion are removed using explosives torotate the domed structure about the reaction line and the pivotingmechanism to demolish the domed structure. The pivoting mechanism can bea roller cam or a hinge and the removal of portions of the remainingdome-supporting wall using explosives can be done after the domedstructure has begun to rotate. For example, explosive charges can beplaced vertically in the remaining wall portion as part of thedemolition.

[0012] Water can be applied to all or part of the domed structureduring, before and/or after use of the explosives and the dome can besegmented radially, if desired. Preferably, the domed structure is anuclear reactor, but other structures can be subjected to the inventiveprocess.

[0013] Prior to demolition, one or more materials may be wrapped arounda portion or all of the domed structure and backfill can be added to thedomed structure base, if necessary.

[0014] The invention also includes the domed structure as modified fordemolition, wherein the domed structure has a domed roof and a roofsupporting wall. The improvement in these structures is the existence ofa hinge or pivoting arrangement positioned in the wall, the hingearrangement adapted to rotate the domed structure along a reaction linefor demolition purposes.

[0015] The hinge can be a roller cam mechanism or use opposing arcuatehinge surfaces formed in the wall. Legs can be formed in the wall downfrom the hinge arrangement, removal thereof assisting in rocking of thestructure. Other openings can be made in the dome to facilitate isdemolition such as in the wall to facilitate its demolition.

[0016] Another method aspect of the invention includes identifying afirst side portion toward which a dome of the domed structure will falland segmenting the dome portion. Then, a plurality of openings areformed in the first side portion, the forming step leaving a leg betweenadjacent openings. A through slot is formed in a second side portionopposite said first side portion, and a pivoting mechanism is formedeither as part of remaining side portions of the dome or as a separatestructure. The legs are demolished so that the remaining side portionspivot toward the first side portion so that said dome structure cancollapse.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Reference is now made to the drawings of the invention wherein:

[0018]FIG. 1 is a schematic representation of a typical domed structurefor a nuclear power plant;

[0019]FIG. 2 is a diagram showing a demolition fall line for a domedstructure;

[0020]FIG. 3 is a schematic representation of a domed structureconfigured for demolition according to the invention;

[0021]FIG. 3A shows an enlarged side view of an alternative hingearrangement;

[0022]FIG. 4 is a schematic view of the domed structure of FIG. 3 in apartial demolition state;

[0023]FIG. 4A is a schematic view of the dome structure of FIG. 3 in amore advanced partial demolition state;

[0024]FIG. 5 is a schematic view of a demolished domed structure usingone mode of the invention;

[0025]FIG. 6 is a schematic view of prepared domed structure fordemolition with an alternative hinge configuration; and

[0026]FIG. 7 is a schematic view of the domed structure of FIG. 6 in apartially demolished state.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The present invention is a significant advance in the demolitionof buildings, particularly domed structures for nuclear power plantsreactors.

[0028] Referring to FIGS. 1-5, one mode of the inventive method isdepicted that employs a domed structure 10 for demolition. Although thedomed structure can be any type, a typical domed structure would be anuclear power plant reactor. These structures are quite massive and canbe 144 feet in diameter, have a dome height of 70 feet, and have anabove ground elevation of 148 feet, a total structure height of around170 feet, see FIG. 1.

[0029] The structure 10 has a dome 1, a cylindrical wall 3, and afoundation/base walls 4. The cylindrical wall 3 and dome 1 are generallyconstructed with a steel liner and an overcoating of concrete. Manytimes, the steel liner has studs extending outwardly so that theconcrete has additional anchoring surfaces for bonding to the liner.

[0030] A first step in demolishing the structure 10 is to fill the basewith a backfill 5 so that the debris is at grade for removal. The use ofthe backfill may be optional if the domed structure does not extendbelow grade.

[0031] Next, a number of operations are employed to configure thestructure for a fall along a specified direction or fall line. First andas shown in FIG. 2, a fall line “A” passing through the center “C” ofthe dome is determined. The fall line also defines a reverse fall line“B” and a line “D” that is perpendicular to the fall line and passingthrough center “C”. Next, a reaction line “E” is sited behind line D.The reaction line is the line on which the dome will pivot and fall inthe direction of fall line “A.”

[0032] Referring to FIGS. 1 and 3, and once the reaction line isidentified, a pair of pivoting mechanisms or hinges 7 (only one shown)are formed in each side of the wall 3 of the structure. The hinges 7 areformed by making a pair of arcuate cuts through the wall 3. A straightcut 11 is also made in the wall portion 13 which is opposite the wallportion 15, and which spans between the two hinges 7. The outer surfaceof the wall portion 15 faces the fall line “A.” Shims or the like (notshown) can be used to prop up the wall portion 17, if desired. It shouldbe understood that the cutting or severing can be done by any knownmeans, such as a wire saw, thermal means, or combinations of differentmeans.

[0033] Referring to FIG. 3A, the pivoting mechanism or hinge 7 can bestrengthened by interposing steel plates 21 and 23 between the concretesurfaces 25 and 27. This forms a stronger and more crush-resistanthinge. The steel plates can be modified with studs 29 and a grout layer31 for bonding to the concrete surfaces as well.

[0034] The hinges could have any dimension depending on the size of thedomed structure, e.g., a 4 foot or even a 10 foot radius.

[0035] Referring to FIG. 3 again, once the hinges 7 are formed and thewall portion 13 is severed, a number of through openings 33 are made inthe wall portion 15 by cutting, etc. The openings would be made byremoval of both the concrete and steel, but the concrete could beremoved and the steel could be merely cut to follow the opening shapeformed by the concrete removal. Formation of the openings 33 creates anumber of legs 35 that span the side between the two hinges 7. Theheight of the openings is sufficient so that an eccentric load iscreated, and should extend beyond the elevation of the line 11.

[0036] The dome 1 is also segmented or severed along the lines 39 usinga wire saw or the like to form dome segments 41. Preferably, the cutgoes through both the steel liner and the concrete outer shell, but justthe concrete could be severed. If the steel liner cannot be cut,explosives could be used to cut the steel liner in several predeterminedplaces to facilitate dome segment separation. This radial precuttingpermits the dome to stand safely while the overall dome is in itsoriginal position. However, the pre-cut dome parts would come apart onexplosion. Explosives could also be placed with the dome segments 41 toassist their separation.

[0037] Then, explosive charges are placed on the legs 35 to remove them.The explosives can be placed by first drilling horizontal holes into orthrough the legs 35 and placing the explosives in the holes. Of course,other shaped openings can be employed, e.g., vertical or diagonal slotsor through holes, and the like. The explosives are then detonated toremove the legs 35. Once the legs 35 are blasted out, an eccentric loadis formed as shown in FIGS. 4A and 4B whereby the dome 1 and remainderof wall 15 and wall 13 rotate or pivot about the reaction line andhinges 7.

[0038] Referring now to FIG. 4, another option is to vertically placeexplosives in the side wall portions 13 and 15 around a periphery of thestructure 10, including if desired above the hinges 7 to assist thedemolition. The explosives could be placed in holes 43 in the wall 3that are positioned vertically, but the holes could take on otherconfigurations, e.g., horizontal, diagonal, or in various combinationsthereof if desired. As the dome 1 rotates, the explosives could bedetonated to demolish the structure 10 as shown in FIG. 5, wherein thedome segments 41 as well as wall segments 45 collapse along the fallline “A”. This step, although optional, would better assure that thedome structure does not merely rotate to the position shown in FIG. 4Aand come to rest without separation of the dome segments 41. FIG. 4A isshown with the openings 43 but as though explosives were not employed toassist in demolition of the wall 3 of the structure 10.

[0039]FIG. 6 shows an alternative eccentric load creating configuration50. In this embodiment, roller cams 51 are used (one shown) rather thanthe hinges 7. Each roller cam 51 has a cut line 53 similar to line 11 inFIG. 3. The cut line 53 and remaining opening or notch 54 leave a camsurface 57 as part of the wall 3, which allows the dome structure 10 torotate. In this embodiment, the pivoting mechanism is formed out of theside portion such that the roller cam acts as the pivot, whereas thehinge of FIG. 3 is formed in the side portion such that the two opposingsurfaces co-act during rotation of the structure.

[0040] After the openings 33 are made in the wall 15 to leave legs 35,and the legs are removed using explosives, the remaining structure 10will rotate as shown in FIG. 7. The blasting of the remaining wallstructure can be done as is explained above and shown in FIGS. 4, 4A and5.

[0041] One advantage that the roller cam design has is that it avoidsthe problem of the hinges binding before the dome structure rotates.With the roller cam design, the space formed by the notch 54 eliminatesany surface that could interfere with the cam surface 57 duringrotation.

[0042] Control of the falling of debris can be achieved by the use ofprotective netting or mats. Plastic or metal fencing, curtains of wovenmaterials like wire, cable, rope, curtains of non-woven materials suchas spun bound polypropylene geotextile fabric or other types ofmaterials can be suspended or placed in front or around the structure tobe demolished. These materials can be used alone or in combination,e.g., a double wrap of chain link fence, with a double wrap ofgeotextile fabric around the fence.

[0043] It should be understood that the explosives for use in the domedstructure demolition are all well known in the art and a furtherexplanation is not deemed necessary for understanding of the invention.

[0044] Vibration that occurs during the demolition process can bemitigated by the use of cushioning materials placed in the appropriateareas when material are to fall, e.g., in the fall line, around theperiphery of the structure, within the periphery of the structure, etc.The materials can be any type suitable to consume the energy existing inthe descending debris, e.g., sand or other particulate material.

[0045] Since dust is always a problem in the demolition of buildings,dust suppression and/or collection steps can be taken before, during,and/or post demolition. One technique would include covering or layeringthe explosive charges with water containers such as hoses, bags, vesselsor the like. Upon detonation, the water in the containers would suppressdust generated and assist in controlling of flying debris from thedetonation.

[0046] An alternative technique involves the use of a wet layer offlexible material such as a geotextile fabric placed over the structure,i.e., a wet blanket.

[0047] Another alternative is to create hydraulic envelope around thestructure and its fall area. In this technique, water is sprayed in thevicinity of the structure. The water can be augmented with additivesthat would reduce its surface tension such as surfactants. This wouldpermit the formation of smaller water droplets and more efficiently wetdown airborne particulate matter. In place of water, a superheated steamcould be employed. The use of superheated steam should result in theproduction of a fog bank or fog-bank like environment due to the steamsgeometrical expansion when contacting lower temperature air.

[0048] The different dust suppression and elimination techniques can becombined together in various fashions to augment each other. Moreover,filtering and/or collection systems can be employed when using water sothat any objectionable material entrained in the water or mist can berecovered without contaminating the environment.

[0049] As such, an invention has been disclosed in terms of preferredembodiments thereof which fulfills each and every one of the objects ofthe present invention as set forth above and provides a method fordemolishing domed structures and a modified dome structure to achievesuch demolition.

[0050] Of course, various changes, modifications and alterations fromthe teachings of the present invention may be contemplated by thoseskilled in the art without departing from the intended spirit and scopethereof. It is intended that the present invention only be limited bythe terms of the appended claims.

What is claimed is:
 1. A method of demolishing a domed structure havinga dome and dome-supporting wall comprising: segmenting a dome of thedomed structure; forming a pivoting mechanism in side walls of the domedstructure along a reaction line; forming openings in a opposing wallportions, one wall portion facing a direction of intended fall; andremoving support portions of the one wall portion using explosives torotate the domed structure about the reaction line and pivotingmechanism to demolish the domed structure.
 2. The method of claim 1wherein the pivoting mechanism is a roller cam or a hinge.
 3. The methodof claim 1, further comprising removing portions of the remainingdome-supporting wall using explosives after the domed structure hasbegun to rotate.
 4. The method of claim 1, further comprising applyingwater to all or part of the domed structure during, before and/or afteruse of the explosives.
 5. The method of claim 1, wherein the dome issegmented radially.
 6. The method of claim 1, wherein the domedstructure is a nuclear reactor.
 7. The method of claim 1, wherein one ormore materials are wrapped around a portion or all of the domedstructure prior to demolition.
 8. The method of claim 3, whereinexplosive charges are placed vertically in the remaining wall portion.9. The method of claim 1, wherein backfill is added to the domedstructure base.
 10. The method of claim 2, wherein opposing steel platesare used in the hinge to facilitate rotation thereof.
 11. In a method ofdemolishing a structure using explosives, the improvement comprisingforming a pivoting mechanism in a wall portion of the structure todirect the structure along a predetermined fall line.
 12. A method ofdemolishing a domed structure comprising: identifying a first sideportion toward which a dome of the domed structure will fall; segmentingthe dome portion; forming a plurality of openings in the first sideportion, the forming step leaving a leg between adjacent openings;forming a through slot in a second side portion opposite said first sideportion; forming a pivoting mechanism as part of remaining side portionsof the dome; demolishing the legs so that the remaining side portionspivot toward the first side portion so that said dome structure cancollapse.
 13. A method of claim 12, wherein the pivoting mechanism isformed in the remaining side portions using opposing co-acting surfaces.14. A method of claim 12, wherein the pivoting mechanism is formed fromthe remaining side portions to provide a rotating surface.
 15. In adomed structure designated for demolition, wherein the domed structurehas a domed roof, and a roof supporting wall, the improvement comprisinga hinge arrangement positioned in the wall, the hinge arrangementadapted to rotate the domed structure along a reaction line fordemolition purposes.
 16. The domed structure of claim 15, wherein thewall includes a plurality of legs between first wall openings having anelevation greater than an elevation of the hinge arrangement.
 17. Thedomed structure of claim 15, wherein the domed roof has a plurality ofradial openings to form separations in the domed roof during demolition.18. The domed structure of claim 15, wherein the wall includes a numberof second wall openings to receive explosives to facilitate demolition.19. The domed structure of claim 15, wherein the hinge arrangementfurther comprises a pair of paired opposing arcuate surfaces.
 20. Thedomed structure of claim 15, wherein the hinge arrangement furthercomprises a pair of cam surfaces.